System and apparatus for automatically steered towed vessels

ABSTRACT

A system and apparatus for automatically steering vessels under tow by employment of forces transmitted through tow cables that operatively connect a vessel being towed with its towing vessel so that the towed vessel travels substantially in the path of the towing vessel, by automatic rudder changes at various turning speeds to accommodate for changes in course while being towed. The tow cables from the towing vessel are operatively connected on the towed vessel to a towing and steering mechanism that allows the cables to effect rotation and/or translation of a pinion mechanism that is operatively connected to and controlled by a rudder turning means to effect turning of the rudder or rudders on the towed vessel when changes in course are required.

[22] Filed XR 3 96 l 1 a 977 SR Inge Gordon Mosvold R0. 80: 58, Freewrt, Bahamas I21 1 Am. No. 881,938

Dec. 3, 1969 Oct. 12, I97 1 {45] Patented Continuation-impart of application Ser. No. 706,968, Feb. 20, 1968, now abandoned.

SYSTEM AND APPARATUS FOR v AUTOMATICALLY STEERED TOWED VESSELS 26 Claims, 15 Drawing Figs.

US. Cl 114/236 Int. Cl B631, 21/00 Fieidof Search 1 14/235,

References Cited UNITEDSTATES PATENTS 394,174 12/1888 Grignon 114/236 1,968,577 7/1934 Taylor 114 236 Primary ExaminerTrygve M. Blix Attorney-Stevens, Davis, Miller & Mosher ing vessels uncle low by employment of forces transmitted ron h tow cableswthatnperalively connect a vessel being towegLqvjthjjstowihg vessel so that the towed vessel travels substantially in the path of the towing vessel by antometic -fifddeighanges at vggioggjemingspeedsto aecommodate full changes in coursey hjle being towed. The low cables from the Towing vessel are operativeiy connected on the towed vessel to a towing and steering mechanism that allows the cables to effeet rotation and/or translation]???- pinion mechanism that is operatively connected to and controlled by a rudder turning means to effect turning of the rudder or rudders on the towed vessel when changes in course are required.

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SYSTEM AND APPARATUS FOR AllTOMATlCALLY STEERED TOWED VESSELS CROSS-REFERENCE TO RELATED APPLICATION "1, 7 BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to a system and apparatus for automaticallYEe'e'riiig towed vessels by utilizing variati rs in the tbnsion or stress on the towing c'ables be tween a towing vessel land one or more vessels being towed. More particularly, the system and apparatus of this invention concerns its automatic QBEQL msstfi the eds srunsshan smsitw d.

Zessels tdfiifiect, it" appropriate times, continuous variable corrections in the course of the towed vesselsso theylwill fol-:

low the towing vessel and in addition, ag ommodate simul- :tan ebusly, if heeded, any mbiion such as pitching, heaving and; yawing of the vessels and thus provide for quickrecovery from ilse mnt ck s- Description of the Prior Art A major difficulty in the deep sea towing of vessels, particularly in rough water, is maintaining the towed vessel on the same course as the towing vemel without excessive wandering across the desired course. Many mechanical devices have been proposed, but these rely on a direct or constant movement of the rudder of the towed vessel with changes in angle of the tow cable as the relative position between the vessels changes and many are excessively complex. Towing vessels at sea isparticularly hazardous because of vessel inertia as cf fected by wind, waves, water currents, and crosscurrents, all of which continually vary the foreces operating on the huii of the towed vessel causing it unpredictabiy to change course while pitching and heaving, thus making the'steering of the towed vessel very difficult to control. This lack of control becomes a major factor when the towed vessel or tow encounters high waves and heavy wind, and the devices of the prior art do not provide satisfactorily for a quick and simplified accommodation of both vessel inertia under surging movements and utilization of the disturbing forces to effect a continuous, adjustable control of the course of the vessel under tow. Also, the prior art controls have difficulties in providing the necessary instantaneous rudder control where the towed vessel is 1 designed with hull lines corresponding to the shape of seagoing ships, for these types of towed vessels must have a rudder control that will quickly respond to changes in course of the towing vessel while not overcorrectingwhen it is necessary to correct for course change. I

The problems and disadvantages presented by prior art devices known to the inventor are satisfactorily overcome using the system and apparatus of this invention which provides an automatic steadying and steering device capable of responding quickly and effectively to changes in tension occurring in the towed cables as the course of the towed vessel of vessels must be changed to follow the towing vessel closely,

particularly when towing at sea where pitching and heaving of a a towed vessel is accentuated. I

While the invention will be described primarily in reference to a single towed vessel it will be appreciated that the invention equally applies to towing a plurality of vessels in line or in tandem. Accordingly, the invention contemplates automatic steadying and steering of each vessel under tow in response to variation in forces on a tow cable on a towing means that links the vessels together, by providing a rudder-turning assembly that has means for selectively producing both rotating and translating motions as the forces are varied in the tow cables to effect the turning of the towed vessel when a translational motion is produced and to compensate by rotary motion for producing a combination of the rotary and translatory movements to amplify or to slow the speed of towed vessel rudder response to disturbing forces automatically within varying portions of the available angular rudder travel. This action provides the advantage of adjusting towed vessel turning response to be accelerated or deceierated according to the relative positions and headings of the vessels and the disturbing forces acting on 'them which effectively maintains the towed vessel on a closely following or tracking course to that of the towing vessel. Also, the apparatus of this invention provides for the amplifying of the speed with which the bridle cable transmits turning moment to the rudders to provide for various degrees of speed in rudder response.

The towing means advantageously can be in the form of a bridle cable arrangement in which one cable is attached to the towing vessel and leads to a bridle or yoke from which a pair of cables extend onto the towed vessel and are operatively connected to a towing and steering means. It will be appreciated that the towing cables can be in the form of chains, wire, or fibrous-type lines, ropes, or the like. In operation, towing force present in the pair of cables provided by the bridle arrangement pass in two force-transmitting paths that are provided in the towing and steering means by a pair of forcetransmitting cables which preferably run towards the aft end of the towed vessel along its port and starboard sides. A rudder-turning means in the towing and steering means coupies the transmitted forces to the rudder mechanism and has mechanism that produces either a rotating or translating motion or both, so that movement of the rudder can be controlled thereby to change the course of the towed vessel to that of the towing vessel. This rotating and translating mechanism can be in the form of a double rack and pinion arrangement with the pinion operatively coupled to a rudder means or steering device so that the pinion rotates when the racks are moved equally in opposite direction; or rotates and translates when the racks are moved uncquaiiy or differentially in opposite direction or in the same direction; or translates when the racks are moved equally in the same direction. Thus, pinion translation acts to effect the change in course of the towed vessel while pinion rotation without translation produces substantially no change in vessel course but, in the main, accommodates for pitching and heaving of the vessel to steady it in its course.

The rotating and translating mechanism can be a single set of opposed double racks operatively intermeshed by a pinion and each one of the racks operatively connected to a bridle cable and to a rack return mechanism so that as the racks move inthe same direction, or if one rack moves more than the other, the pinion is translated, and by being operatively connected to the rudder or rudders, the vessel is then turned to guide it to a course that follows the towing vessel. When both racks are moved equally in opposite directions, the pinion is only rotated so rudder turning is not effected and vessel drag is not varied adversely as surges in the bridle cable forces are accommodated by extensions and contractions of the length in these cables.

For producing adjustable variation in the speed of rudder response, the rudder turning means advantageously can include a plurality of sets of double racks with a pinion operatively engaging each set of r c !n the plural double rack and pinion arrangements, one set of racks is operatively connected to the bridle cables andcan drive the other set or sets of racks which operatively connect to the rudder means. Each pinion is connected to the other so the pinions transiate in unison thereby causing at least one of the-racks in each set to operate on pinion translation. The connection of the pinions is such that rotation of the pinion in the driving set of racks can be independent of the rotation of the one or more pinions in another of the sets of racks so that \cssei and cable surging can be accommodated without turning of the rudder or setting up strainsltending to throw the vessel off a tracking course. lt

nt-Ma am others by holding one of the racks of a set stationary with respect to its opposite rack and by having one or more addi- I bridle cables so that the stresses produced in these cables'will cause lengthening or shortening of the cables, causing the "racks'to' move'so'as to turn itspinion in rotation and/or translating it. A second set or sets of racks can then be carried on a held in various fixed positions. When one of the racks of the second set is maintained in, fixed position with respect to the carriage and another rack which is connected to the rudder,

can be moved or held fixed with respect to the carriage, then when the carriage is stationary, the rudder will be moved at a faster rate than pinion translation, and when the carriage is released to move, the rudder will move at the same rate as pinion translation or at a relatively reduced speed.

It will be appreciated that such organization can provide for the rudder to move at the relatively faster rate in a zone or rapid rudder movement which can shift about within a larger zone of nidder travel so as to adjust speed of rudder reaction to the disturbing forces acting on the vessels. Consequently, in the system and apparatus of this invention, when the towed vessel is tracking well to the towing vessel, the rudder operats in an angular zone close about either side of center with the more rapid rudder response in the small rudder angles that are less effective, so as to quickly correct towed vessel heading. When the rudder operates outside the center zone, that is, at the greater or more effective turning angles, rudder response is slowed to prevent overcorrecting of vessel heading. Also, when correcting from a wide rudder angle, returning of the rudder towards the area of centered position wiil be at the rapid speed; and when the'center area is reached, rudder response is slowed to prevent the undesirable overcorrecting of vessel heading.

The foregoing objects and advantages, and others, flowing from the inventive concepts herein will become more apparent from the annexed description and drawings of preferred embodiments of the invention, that are presented as illustrative and not as Iimitative of the concepts of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view showing a towing vessel pulling the towed vessel using the system and apparatus of this invention,v

and in broken lines relative positions of the towed vessel when off track so that the bridle cables are lengthened on one side and shortened on the other to cause turning of the towed vessel rudder;

FIG. 2 is an enlarged fragmentary plan view of the stern area of the towed vessel of FIG. 1 showing the mechanism of the rudder turning means coupled to the steering mechanism or rudder means;

FIG. 3 is an enlarged fragmentary plan view of the bow portion of the towed vessel of FIG. 1 showing the towing bridle cables connected through the shock absorbers or buffering means to the force transmitting cables of the towing and steermg means;

HS. 4 is a fragmentary view in elevation of the mechanisms shown in FIG. 2 taken along line 4-4 thereof and showingtheir arrangement with respect to the rudders and the stern of the towed vessel;

FiG. 5 is a sectional view in elevation of the tiller pivot post a y taken along line 5-5 of FIG. 4;

Fit 6 is an enlarged plan view of a portion of the in 4 taken aiongiined-d thereof, showing 2v air-waning mechanism with IIS top plate or safety mm d ove from the carriage to reveal the set of upper or ouble racks and pinion, the connection thereof to the carriage that can be moved in translation with the pinions or rudder mechanism or mans and the escapement mechanism which looks or releases thec'arriage;

FIG. 7 is an elevational view of the rudder turning mechanism taken along l'me7-7 of FIG. 6;

FIG. 8 is a plan view taken along line 8-8 of FIG. 7 showing the arrangement in the rudder turning mechanism of the set of lower or driving racksand pinion set;

FIG. 9 is an elevational view taken along line 9-9 of FIG. 6;

FIG. I0 is an elevational view taken along line 10-10 of FIG; 6' showing the carriage release or v escapement mechanism;

FIG. I] is a schematic plan view of a portion of the mechanisms of FIG. 2 showing the operational relationship of movement of the pinion shaft and upper pinion to the corresponding rapid movement of the rudders about a centered rudder position in relation to total available rudder travel;

FIG. 12 is a schematicplan view similar to FIG II showing the readjustment of the rapid or fast zone of rudder travel with respect to available ruddermvel when the carriage is moved;

7 FIG. I3 is a schematicplan view similar to FIG. I2 showing the carriage moved to its extreme limit which has repositioned the zone of fast rudder travel to its extreme position;

FIG. 14 is a view in perspective of a towed vessel utilizing a simplified arrangement of force transmitting cables and racks and pinion; and 1 FIG. 15 is a plan view showing a towing vessel pulling a series of towed vessels each using the system and apparatus of this invention.

DESCRIPTION sel is by means of a tqlcableil hag n g 'giie''nd sawmills 2b of the 03115; vessel and the other end connect a pai bridle cables, that connect neaa towing ndst sfiss z -ssh smsa f1 rasfifi3 thetowed vessel The tow or towed vessel 22 is shown in FIG. I in solid lines being towed on-track that is, on the course of the towing vessel, and in broken lines in two off-track" positions, to port and to starboard of the course of the towing vessel so as to indicate how the length of one bridle cable is lengthened more than the other with respect to the towed vessel. This change in bridle cable length occurs when the towing vessel changes course or heading and as the towed vessel is moved by the other disturbing forces on'it of wind and water action.

The towed vessel has a hull with a bow 30, port and starboar St e arson's: and 32a, and a stern portion 34'wherejfis'p't o vided with a steering mechanism or rudder mcans36' mafia steering that includes apair of port and starboard rudders 3s and 38a. A deck 40 extends across the b ow of tire towed vessel along the top sides. and across the stern portion around central cargo holds 42. The declt thus provides means to s uppgrt the t qwi ng and sreering rneansg fi out of the way of the areas of the holds along the vessel sides and at fore-and-aft positions on the deck. The tow cable can then be operatively connected with the rudders of the towed vessel so as to freely transfer tow cable forces to both tow and steer the barge by pulling it and controlling its rudder action. I

The towing and steering means 28 includes port and starboard force-transmitting cables 46 and 460, each of which has one of the bridle cables connected thereto. The force-transmitting cables in turn are connected with a rudder turning means or mechanism 48 that is coupled to the rudder means or vessel steering mechanism 36 through a rudder coupling means or device 50 which form a part thereof. The turning means 48 and the coupling means 58 together provide for actuating the rudders whentovr cable forces are changed.

,In FIG. 1, the rudder couplingdevice 50 is operatively connected to the rudder turning means 48 by the forward end of a tiller 54 which is pivotally attached thereto and supported w of the towed abovethe deck 40sliding on a tiller guide 55 for side-to-sicle swinging movement about a pivot post assembly 56'. This assembly supports'a tiller pivot post 58 on a pair of fGl'C-(ifid-Kf! arranged, spaced horizontal beams 60 that are supported in turn from upstanding stanchions 62 attached to the towed vessel deck. It can be seen that the horizontal beams are provided with spaced, pivot positioning boltholes 64 and bolts by which the tiller pivot post assembly can be adjusted along the tiller to ilarious fore to aft fixed positions with respectthereto so as to provide a variably locatable fulcrum for changing the leverage and specdof turning of the rudders when the tiller is pivoted about the pivot post to accommodate various types of towed will be understood that turning of the tiller produces a sliding motion of it'with respect to an upper fulcrum plate 67 and the flange which provides the'tiller with its aftersupport.

Further making up the rudder coupling device 50 is a rudder swing post 68 that is vertically supported in the tiller slot 66 aft of pivot post 58 between a pair of post plates 69 then held by a'supporting cotter pin 70. The latter plates provide for the swing post to slide in the tiller slot when the tiller is moved to port or starboard. The swing post has its lower end fixed to a central horizontal pivot arm 72 that has a vertical leg connected to the hull to pivot at 73. For pivoting the rudders a pair of port and starboard rudder arms 74 and 74a respectively, are pivotally attached at their afterends to a rudder crossbar 76 which operatively connects them for joint movement when the tiller is swung over. As the rudder arms are fixedly connected at their forward ends to a pair of port and starboard rudder posts 73 and 73a pivc-table in it e hall to turn their respective rudders, it will be understood that all rudders will be turned in unison when the tiller is swung to port or starboard as the bridle cables are extended or lengthened or retracted or shortened in fore-and-aft direction with respect to the towed vessel. I

It can be seen that the tow cable 24 extending from the stern of the towed vessel can be connected there at one end to a winch 82 and then extended through a fair-lead a suitable towing distance aft of the tugboat for towing operations. Forward of the towed vessel, the tow cable is divided at a yoke 84 to form the bridle 26 and provide the port and starboard bridle cables, 86 and 86a, of equal length along which forces acting on the tow cable are directed to port and starboard outboard sides of the towed vessel. The towing and steering means or mechanism 28 to which the bridle 26 attaches has identical force-transmitting and modifying mechanisms in almost mirror opposite arrangement along port and starboard sides of the towed vessel where they form separate force-transmitting paths linking the bridle cables to the rudder turning means 48.

As will have been noted, in the drawings, identical units on the starboard side to those on the port side are designated with the letter a," and for simplicity at this point, since they function alike only the units of the port side and their interconnections will be fully described. Thus, each bridle cable 86 and 86extends onto the bow of the towed vessel through a group of two sets of fair-lead rollers 88 and 89 to produce the most desirable included angle between the bridle cables and each of these has its afterend operatively connected to the towing and steering means and thus with the rudders by connecting to a forcemodifying or buffering means L t .rough a shackle 92 connected therewith. The ends or aft extensions of each bridle cable are also held by a clamp 94 to its respective force transfer or force-transmitting cable 46. Such connection provides for separate and independent coupling of forces in the One of the purposes of the buffering means 90 is to prevent the hard shocks due to vessel surging and comprises a hollow cy-inder in which a buffering cylinder shaft or rod 96 carries a spring plate or rod head 98 on its afterend and at its forward end is connected to the shackle 92. A buffering spring 100 is positioned around the shaft 96 so that the rod head will compress the spring against the forward end of the cylinder when the bridle cable lengthens and when it shortens the spring will pressbetween the forward end. of the cylinder and the rod head moving the cylinder rod aft, thus carrying with it the clamp 94 for moving the force-transmitting cables 46 an 46a. it will be appreciated that the cylinders of the buffering means 90 are firmly bolted to the deck or hull of the towed vessel so that only the shaft and spring within them are movable. (See F7333) Each force-transmitting cable is arranged in a loop with the two legs of it extending from forward on the vessel where they loop around a forward roller guide 102 to the afterend or stem of the vessel where they operatively connect with the rudder turning means 48. Thus, on the port side, as

'the bridle cable lengthens or shortens the clamp 94 will move passing around a loop reversing roller guide 108 on the opling paths to the rudder turning means where these forces can act independently for controlling rudder action.

posite side of the vessel. This looping'provides for one leg of a forcetransmitting cable to be connected to one end of one of the racks in the driving set of racks at the rudder turning mechanism, and the other end ofa respective cable is attached to the opposite end of the same rack which completes the loop. in this manner, on bridle cable movement, each driving rack will be moved or translated in balance by its force-transmitting cable either to port or starboard as the cable legs or a loop move in opposite directions around their roller guides.

In order to provide for direct cable pulling on each rack and for movement of both racks to be in the same direction athwartship under turning force but their movement to be in opposite directions under surging forces, the force-transmitting cable on the starboard side has its legs crossed one over the other about midway of the length of the vessel. This same result can be accomplished when the legs of the starboard force-transmitting cables do not'cross by providing for one of the clamps 94 and 94a to be attached one to an inboard leg of its cable and the other to the outboard leg of its cable or in other ways.

The rudder-turning mechanism 48, as can be seen, is mounted at the stern of the vessel forward of the rudder coupling means 50 and is supported above the deck on a baseplate 116 that is supported by horizontal transverse beams 118 held by the upstanding stanchions 62.

The rudder-turning means 48 further comprises .a track plate 120 that is disposed athwartship and horizontally fixed for support on the baseplate. The track plate 120 is formed 'from a pair of spaced-apart channels 122 and 122a having their grooved sides forming the channels facing inward one to the other with endpieces 124 and i240 closing the channel groove at each end in an are which can act as pinion stops. The lower arms of the channels define between them an elongated lower hub slot 126 with upper urfaces ofthc lower arms providing a flat slide track 128. Also, the upper arms of the channels define between them an upper hub slot 130. By this construction, track plate 120 is adapted to slidably support the driving set of two oppomd toothed bars or gear rock: 232 and 134, respectively in the port and starboard force-transmitting aths, together with a pinion 513; pinion 1.36 :ntercom nected between them. This pinion has a can of uoocr and lower hubs that assist it to carry fixed to it ar. upstanding pinion shaftl38 for turning and sicle-to-side or athwartship translation, therewith. The racks are slidably supported on the upper directed face of the lower aims of the channels that 1 splic form the slide track 128 and the lower hub of the pinion is slidably received in the lower hub slot so as to make the lower face of the pinion also slidable on the track 128.

I From the construction above it will be appreciated that as each of the driving racks 132 and 134 is connected by its ends to its respective port and starboard force-transmitting cable, any force-and-aft movement of those cables will cause sliding of one or both of the racks. Such rack movement effects turning or rotating of the pinion 136 and its shaft 138 when the racks 'm'ov'e'i'n opposite directionsorione more-than the other or can carry the pinion in sliding translation movement along the slide track without turning it, or both. (See FIGS. 7, 8 and A rudder speed changing slide block or carriage 142 is mounted above the lower slide track 128 on top of the channcls 122 and 1220 and is adapted to slide on the top surface thereof or be held in fixed position thereon under control of a ing racks, then pinion gear will walk along the stationary or fried rack 162 translating the rudder driving rack at a rate carriage release or escapement mechanism generally indicated by the numeral 144. The carriage is constrained from foreandaft displacement by a pair of fore-and-aft carriageretaining rails 146 which extend up from the top edges of the channels and the carriage is constrained and guided in athwartship movement by guide rods 148 and 1480 which have one end set into the carriage by a head on one end of the guide rods that have their other ends free to move in respective port and starboard carriage guide cylinders 150 and 150a held in positionby guide cylinder support blocks 152 and 152a.

To provide for carrying and moving an upper or driven set of racks and pinion there is defined through the lower center portion of the carriage 142 a slotlike, pinion hub slideway l54 communicating with a large slotlike recess defined through the upper part of the carriage so as to form an upwardly facing shoulder around the slideway. The shoulder and the recess provide a pinion slide bed 156 for slidably supporting on the shcu an app.- pzrucn or "men gear 158 which has a ntral aperture through it by which this gear somewhat loosely fits around the pinion shaft 138. When so positioned, pinion gear 158 is below the top surface of the carriage with the hub on the lower face of the pinion gear slidably received in the slideway 154. The slide bed recess terminates at each end in a curved upstanding wall 160. Still further provided in the upper portion of the carriage at its forward side is forward groove in which a gear bar or driven fixed rack 162 is fixedly positioned with respect to the carriage but can move therewith. in the aft side of the carriage 142 there is defined a T-shaped groove having its center leg opening therethrough with the crossing groove of it opening through the port and starboard ends of the carriage which adapts it to receive a gear bar or driven rudder-tuming rack 164 to slide freely therein and beyond the ends of the carriage. As these two grooves are in communication with the recess in the slide bed the fixed rack 162 and rudder-turning rack 164 can operatively connect with opposite sides of the pinion gear 158, these racks and pinion gear forming the upper or driven set of racks and pinion. The rudder-driving rack 164 is slidable as indicated by the arrow on it in MG. 6 and has a rack arm 166 fixedly positioned on it and extended aft through the center leg of the T-shaped groove. This rack arm is pivotally connected at its afterend to the forward end of tiller 54 by a till r drive pin 168 and thus I twice that of the translation of pinion shaft 138 or the linear movement in the force transmitting cables. Whether or not the driven racks 160'and 162 will be carried athwartship together,

which produces 1:1 ratio of movementas between the translation movement of pinion shaft 138 and the rack 132 that drives the rudder, or whether the rudder-driving rack 132 is free to translate at a 2:1 ratio of such movement depends on whetherornotthe-rack arm'l66' has'beefnmoved athwartship far enough to unlock or release the carriage to move. by tripping the escapement mechanism 144. A safety cover 370 that is slotted to accommodate the upper end of the pinion shaft 138 normally closes over the top of the carriage and is h ld thereto by fasteners.

ine particular locations at which the carriage will be unlocked from a temporarily fixed location with respect to the deck of the vessel depends on the points at which the rack arrn I66 near the limits of either its port or starboard maximum travel with respect to the carriage, makes contact against one or the other of a pair of port and starboard escapement trip bars 172 that form a part of the escapement mechanism 144. This mechanism is provided further with a pair of port and starboard spur gears 174 and 1740 capable of rotation on their axes about respective spur gear shafts which support these gears journaled in the aft side of the carriage 142. The spur gears are intermeshed with a toothed bar or escapement rack 175 mounted on the baseplate 116 and fixed gear teeth upward. The lower ends of the trip bars 172 and 1720 are pivoted about a trip bar pin 176, 176a horizontally set in holes in the aft side of the carriage and forming a part of a pair of escapement linkage parallelograms 178 and 178a.

Only the linkage of the starboard escapement parallelogram 1780 will be further described in detail since both port and starboard parallelograms are identical in construction and operation although oppositely arranged. Thus, par gr m 178a has its trip bar 172a pivoted at its upper end to a linit bar 1800 whose starboard directed end is pivoted to a paraliei bar 182a that has its lower end pivotally connected to the aft side of the carriage. Link bar 1804 further carries a pawl 1840 that normally engages in the teeth of its associated spur gear 1744 by the force applied by an escapement spring 186a that biases the linkage of the parallelogram to starboard (See H6. 10). it will be appreciated that this biasing maintains the pawl en gaged in the teeth of its spur gear and prevents the carriage. in the case of the starboard parallelogram, from moving to port by preventing travel of spur gear 1740 on escapement rack 175 until the arm 166 engages the trip bar l72a thereby overcoming the biasing of its escapement spring and pivoting the parallelogram linkage to port. This action withdraws the pawl 284a from its spur gear allowing it to travel on rack 175 so that strikes trip bar 172, the port parallelogram 178 has its pawl 184 released from its spur gear at which time the carriage is unlocked and can then travel to starboard.

provides a link. from the rudder-turning means through the rudder coupling device or mechanism to the rudders.

it will be appreciated that as the driven pinion gear 158 l sely fits over the pinion shaft 138 but is otherwise unconnectcd thereto, that gear can be carried at'nwartship in translation by the pinion shaft without rotating the pinion gear whenever the carriage is free to translate or move back and forth towards one side or the other of the vessel. Pinion gear 158 can (nus act to slide the rudder driving rack {64 at the same fate of translation as the driving pinion 336 when the carriage 15 it ciy movable. when the carriage 142 is not free to move and anslation of pinion gear 153 occurs, for example by W nequal athwartship movement together of the driv- The foregoing description has been made with reference to use of two rudders positioned side-by-side for movement in the same direction together. it will be appreciated, however, that a single, centrally posi ioned rudder or a gang of three or more rudders may be used for steering.

In light of the foregoing, the operation of the towing and steering mechanism shown in H65. 1 through it), that gives the dual smed rudder response and the variation in rudder position and timings of the changeover from one to the other speed, can now be understood with reference to the schematic diagrams of H08. ll, 12, and 13. These schematics are based on the drawing of FIG. 2 an" arn the relationship between fore and aft linear moi in the force transmitiing rabies, as captcssu' iii aiiiwe l Lsiiip iii'icm' .iitfii'fiefii Q: pinion shaft 138 and pinion gear 158, to the resulting rudder angles and variation in speeds of rudder turning under the control of rudder turning mechanism 48. Also, the diagrams .srsamdsutwr" are based on a construction where the rudders turn at the 7 same angle as the tiller is moved. Therefore, angular rudder movement is ills trated with re.erence to the angular position of the till r 54 at the centerline of the towed vessel, for clarity, it being u hderstood that the angles it makes are the same, in this case, as the turning angle-made by rudders 38 and 380 so that it is rudder angle which will be referred to and in terms of turning of the rudder.

- In FlCiS. ll,.l2,.and 13., total available rudder travel is.

shown asan are centered aboutthe' keel line or fore-and-aft centerline C. Also, in these FlGS., the shaded areas are representative of arcs of fast rudder travel and the unshaded areas of arcs of slower rudder travel produced in accordance with one aspect of the invention. Thus, with the apparatus of FIGS. 1 through 10, rudder turning at the fast or 2:1 ratio and the slow or l:l ratio of the linear translation of pinion gear I58 with respect to the linear translation of the rudder driving rack 164 are shown respectively in the shaded segments or angles x of rudder turning arc and the unshaded segments or angles y" of rudder turning arc. Linear translation refers to the positional movements between port and starboard or between right and left in the diagram. The ratios could also be taken as the ratio of speed of rudder turning to the linear board. This movement, in turn, either leaves the driven pinion gear 158 undisturbed when the shaft only rotates or spins in its aperture or slides and/or rotates the pinion gear in translation when theshal'i. is translated.

in the schematic diagrams, the pinion gear 154 is shown in a centered position in the carriage 142, in which case the ruddots are centered in their respective zones of fast travel and the pinion gear is shown at its athwartship fast travel limits A and B to port and starboard with respect to the carriage 142. When the pinion gear has reached these limits, the position of the rudder driving rack has been moved to place its rack arm 166 at its port or starboard limits which are the points of carriage release A and B corresponding thereto where the carriage is released for translation.

As long as the upper pinion gear operates only between its starboard and port fast travel limit positions A and B, by slid not travel so the rudder is turned at the fast speed or 2:l ratio between its fast turning limits A" and B" which are the corresponding positions to A and B.

However, whenever the driven pinion gear has moved arm I66 beyond the points of carriage release in the manner heretofore described, it carries the fixed rack 162 (and thereby the carriage) and rudder driving rack 164 insliding translation together athwartship as the pinion gear is moved by the shaft 138. Should the disturbing forces of towing, wind or seas effect a reversal of pinion shaft translation towards an opposite direction at any time the carriage is being translated at the slower lzl ratio, then the rack arm 166 is thereby disengaged from its hold against one of the trip bars 172 or 172a and the linkage of the respective parallelogram is pivoted back to the "locked" position of HS. 16 by the respective escapement spring iSfi or 1860 pivoting its trip bar about a trip bar pin 176 or 17% whic reengages the pawls 134 and 184a with the proper spur gsgm's 17d nr 1741:, The carriage is thereby again locked in a position fixed with respect to the baseplate 116 and the vessel declt whenever the carriage may happen to be at the time of reversal of the travel of shaft 138 and pinion gear I58.

in FIG. 11, centered rudder position is shown by the'position of the rudder arms Hand 74a and tiller 54 in solid lines in center positions (I) and in broken lines the positions of fast rudder turning limit A" and B" to port and starboard of centered rudder when the carriage 142 is centered and-locked. Any disturbing forces acting to turn the rudders to either port or starboard limit (the edges of the shaded areas) would cause the carriage to be unlocked for movement by engagement of rack arm l66 with the respective trip bars 172 or 172a to allow further rudder travel, as represented by the unshaded areas, at the slower 1:! ratio. In this FlGURl-I, the sliding of driving racks 132 and 134 has not caused the driven pinion gear 158 to move the carriage but only to move in the slide bed 156 in the positions indicated with respect to the vessel deck. it will be observed that the rudder is thus moved, through smaller angles or arcs to either side of centered rudder where vessel turning moments produced are relatively small, at the rapid speed, so as quickly to catch and correct errors in the course of the towed vessel as the driving racks are moved to port or starboard or both by the action of the tow cable on the force-transmitting cables. Should both driving racks 132 and 134 be translated equally athwartship as by surges in the tow cable from directly ahead, the driving pinion gear 136 is merely rotated in place between its oppositely moving driving racks and the pinionshaft 138 slips in the aperture in the upper pinion gear and thus does not transfer any Surging forces to the upper set of racks and pinions or to the carriage 142, which relieves strains on the mechanism and steadies the vessel on course by not effecting rudder movement.

in FIG. 12, the bridle cables have moved the driving racks in the same direction together a distance which has caused them to carry pinion shaft 138 between them to port a sufficient distance from that in FIG. I! so that rack arm 166 has tripped the escapement linkage of parallelogram 173a and has released the carriage I42 for movement. This has allowed the carriage to be carried to port so that the pinion gear fast travel limits A and B have been positionally adjusted to port with the rudder turned to position ll corresponding to rack arm 166 movement to A as the pinion gear is moved to A It will be appreciated that in this action when starting from the midship or centered rudder condition of H0. 11, the rudder has moved from position I to the limit of segment A: of that figure at the faster speed and then has moved at a slower speed therefrom to reach position ll of HG. 12. Thus, as rudder angle has increased, with a consequent increased turning moment on the towed vessel, the speed of rudder movement is decreased in the larger rudder angles for preventing overcorrecting of towed vessel heading. It will be clear that this action has adjusted or repositioned the area or arc .r through which the rudder can be moved at the higher ratio of speed with respect to that shown by the shaded area 1 in FIG. 11. This permits at the greater rudder angles and turning moments a quick countercorrection of rudder angle in the opposite direction back towards centered rudder and even (in this case) somewhat over center to quickly correct any tendency for the greater rudder angles to overcorrect the heading. Also, any continued rudder turning past center C starting from position ll would be at the slower speed assisting to preve at a too rapid countercorrection. Should ruddecorrection again occur in an opposite direction, that is, towards centered rudder, the rudder can again turn at increased speed. "D2252 actions assist to prevent the undesired wandering or wide oscillation of the towed vessel about the desired course.

in FR]. 13 the disturbing forces and/or tow cable force has moved the carriage X42 beyond the position of it shovm in FIG. 12 so it is fully to port. in is position, the rudder has reached the extreme of its an... trove as indicated by its position lll which gives the greatest vessel turning moment. Also, the area of fast rudder travel ha been repositioned in the manner described by FIG. 12 to lie wholly to one side of vessel centerline C. This allows the rudder to correct in the opposite direction all the way from maximum rudder travel to v MNWW .1 may;

it can be seen in FIGS. ll, 12, and 13 that the zone of rudder travel at fast speed x is one-half the total rudder travel. However, it will be appreciated that the carriage may be constructed or have means to more narrowly limit the translation movement of the pinion gear 158 to provide for the angle through which the rudder is turned at the faster speed to be less than one-half the total available rudder travel, or it could be someivhat greater than half. in the first stated of such additional embodiments, when the fast zone of rudder operation has not passed beyond centered rudder position, rudder operation is as heretofore stated with regard to the foregoing embodiment, but when the rudder has traveled to one of its maximum turning limits the zone of fast rudder travel x is moved to port or starboard beyond a centered rudder position speed the responsive movement of these cables to forces ap plied to them. Such dampening means can, for example, be in the form of one or more hydraulic or neumatic cylinders, or

both, in which a piston and piston rod is movable in a dampen ing fluidwith the piston rod extending through an end of the cylinder and operatively connected by clamps or other means to its respective force-transmitting cable. Various fluid control in which case the return or countercorrection movement of with the remainder of rudder return to center at the slower speed where the turning moments are less effective, for preventing overcorrection of vessel heading.

lt WE! be appreciated that the ratio of rudder turning speed can be varied by use, for example, of additional rack and pinion set at the rudder turning means 48 or elsewhere in the system, e.g. in the force-transmitting cables. Good results have been found with this invention when ratios are used from about 1: to about l:5 in the variations between linear movement in the force transfer cables to speed of rudder turning.

it should also be pointed out that with this invention, adjustment of the size or angle of the fast zone of rudder travel x relative to the total arc or angle of available rudder turning can be made by selective i'ore-and-aft positioning of the tiller pivot post assembly 56 which alters the location of the fulcruming of tiller 54. The relative extent of these angles can also be altered by providing adjustable stops limiting the translation of the pinion gear 154 in conjunction with means (not shown} to adjust correspondingly at the escapement mechanism 144 the points of carriage release A and B. Good results in using the system and apparatus of this invention have been found using a fast zone x having about 6 of included angular rudder turning movement (i.e., 3 to either side of a centered mddcr) when total available rudder travel is about 10 to either-side of center (i.e., 20 total available angular rudder travel Satisfactory operation has been found, however, within ranges ofavailablc angular rudder travel of about 30 to either side of center i.e., total available rudder travel of about 60 using zones of fast rudder travel of from about 2 to about 8 angular travel to opposite sides of a centered rudder (i.e., from about 4 to about 16 oftotal fast rudder turning).

it will be appreciated that other means than the driven set of racks and pinion in rudder turning means 48 can be employed j towed vessel heading.

it will be appreciated that the towing and steering mechanism 28 can. be provided with additional controls (not flifig in the port and starboard force-transmitting paths leading to the rudder'coupling means 48 so as to modify the effect of disturbing forces and tow cable action on the ed vessel. Thus, individual force dampening means can be mounted at respective port'and starboard sides on the forward deck of the towed vessel and be connected to the respective P and starboard force-transmitting cables so as to slow or devices, such as valves, also can be positioned in such dampening means to control the rate of force dampening.

A modification providing the vessel steadying of this invention is shown in FIG. 14, in which, generally comparable portions of the mechanism to that of H05. I through l3 are designated by the same numbers used therefor with the addition of double prime marks "to indicate similarities in their function and operation. Thus, bridle cables 86" and 86aextend from the tow cable through port and starboard block fairleads 88" and 88a mounted near the bow of a towed vessel 22" and are detachably connected by turnbucklelike fittings 92" and 92a" to a towing and steering mechanism or means 28 providing elastically extensible port and starboard force paths connecting the tow cable to the towed vessel and its rudder 38 so as to pull and steer it. Two sets of substantially identical mechanisms extend respectively along port and starboard sides with overlapping across the stern of the towed vessel to provide the separate extendable port and starboard force-transmitting paths which operatively connect the bridle cables to the towed vessel rudder through a rudder turning or coupling mechanism or device 48" that independently couples force and movement occurring in the mechanisms of the force-transmittingpaths to the rudder. Principal units of the port and starboard force-transmitting paths are the force modifying spring cylinders 90" and 90a" attached to the es sel deck 40" by their foundation plates; force-transmitting or transfer cables 46" and 460" with their afterroller guides 134" and 13442", port and starboard bar gears or racks 232" and B6" that ha e operativeiy connected beiwecn'them a pinion 136" in the rudder-coupling means or device 48"; and rack return cylinders 220 and 222. A closed loop forcetransfer cable system as previously described may be used for balance to move and return the racks making the return cylinders unnecessary.

Mechanisms of port and starboard force-transmitting paths in FIG. 14 being substantially identical, only that of the port path will be more fully described. Thus, fitting 92" is attached to the forward end ofa spring shaft or cylinder rod 96" which extends axially through openings in the spring cylinder ends and has a shaft head or spring plate 98" attached to it between the cylinder ends near the afterend of the cylinder. The spring plate can slide freely in the cylinder and the rod freely in the openings so the rod and spring plate can be reciprocated when force is applied to the cylinder rod. A helical compression spring 100 of cylindrical cross section is arranged around the cylinder rod so it can be compressed by pulling forces between the spring plate and the forward end of the cylinder.

A force-transfer cable 46" connects by a suitable fitting to the aftcrend of cylinder rod 96" then extends aft around port roller guide 104" to connect by means (not shown) to the port end of the driving rack 132". The starboard end of this rack operatively connects with its rack return cylinder 220 by means of a rack return cylinder rod 224 having a rack return cylinder plate 226 attached thereto and a rack return spring 228 operating in the cylinder 220 between its port end and its spring plate. It wild be clear that this arrangement can provide for returning the rack '132" to centered equilibrium position after it is pulled to port when forces compressing the spring 100" are released. The construction of the rack return cylinder is similar to that of the spring cylinder 96" but may be lighter and have he rack re spring 228 of lowermodulus of elasticity than spring 100". the racks 132 and 23-3 with pinion 136" form a doub e rack and inion rotating and translating mechanism or means for selectively transmitting forces on the tow cable and on the towed vessel and blending them for the desired rudder response during towing.

- translated athwartship.

The rudder turning or coupling device 48" has a bed plate ll6" secured to the decit of the towed vessel so as to have disposed thereon a pair of spaced-apart rack tracks 230 forming part of a slide track in the upper face of the bed. The tracks are arranged on the bed plate in athwartship direction across the central stern portion of the towed vessel so as to slidably receive the respective gear racks 132" and 134". The racks can thus slide on the tracks in opposed spaced relationship with their gear teeth interfitting the teeth of the spur type gear or'pin'ion l36"-;-Th'e pinionisfreeto rotate and also to'= slide on the bed plate along a raised pinion slide or inner bed 156" portion of the slide track as the racks and/or pinion are Pinion 136" also has an upstanding pinion shaft 138 affixed to its center in axial alignment therewith which can rotate with movement of the pinion and be carried linearly athwartship with it. The pinion shaft is suitably supported by means (not shown) so as to remain vertical during translation and rotation. Shaft 138" is also received for sliding movement in an elongated tiller slot 65" defined through the forward end of the tillerthrough which pinion movement in the rudder turning means 48" is coupled to the rudder. The tiller is in turn affixed to a rudder post 78" so when the pinion shaft is moved athwartship rudder 38" will be turned to steer the towed vessel. The system may employ two or more rudders, as will be appreciated.

in operation with the modification of FIG. 14, a pulling force on the tow cable (not shown) acts in its bridle cables 86" and 86a" to transfer pulling and turning forces therein through the respective port and starboard force-transmitting paths so as to pull the vessel and steer by the transfer of the pulling forces to the towed vessel hull and by controlling the ruddertosteer it. Steering results from the extension and contraction of the rack gear portions of the force paths which couple the two cable portions of it in the towed vessel rudder means. ()nly the operation of the m nism of the port force-transmitting path will be more fully described since in essentially the same way.

in operation, an increase in pulling forces on port bridle cable 86" moves it forward relative to its previous equilibrium position pulling cylinder rod 96" forward and extending the length of the mechanism of the port force path as buffering spring 109" is compressed by forward movement of spring plate 98". Spring 100" causes movement of the rod in accordance with the force applied. Pulling forces are thus transferrcd from the tow cable through the spring cylinder foundation attached to the deck, to the towed vessel hull. Where tow cable pulling is greater on one forward side of the towed vessel than at the other forward side due to sidewise deflection of the tow cable or off-track position of the towed vessel, there will be proportionally greater extension in length and greater compression of the buffering spring in the force-transmitting path at the side of the greater pulling than in the other force transmitting path.

Force transfer cable 46" which is attached to the cylinder rod 96" is thus also extended forward by a pull on bridle cablb 86" pulling port rack 132 to port and compressing rack return spring 228 between the cylinder plate 226 and the port end of rack return cylinder 220. This action rotates the pinion 136 and moves it to port if it travels along the teeth of the opposed starboard rack 134" or as it is translated without rotation if racks I32" and 134 move uniformly in the same direction to port as pulling forces increase in one and decrease in the other force-transmitting path the same amount, thus also carrying shaft 138" to port. Port translation of the shaft as it slides in tiller slot 66" pivots tiller 46 about the vertical axis through its attached rudder post 78 and moves rudder 33" to starboard thus tending to turn the vessel as a result of increased pulling forces on the port side of the tuweti vessei.

Pulling forces on the mechanisms of the essentially identical that path from bridle cable 860" through cylinder 90a" and 14 4 along force transfer cable 46a" to pull starboard rack 134" to starboard when pulling forces are increased at starboard. lf

pulling forces are greater on starboard bridle cable 864;" than on port bridle cable 86", then starboard movement of rack 134" causes the pinion 136" interrneshed therewith to move to starboard carrying pinion shaft 138" and pivoting tiller 54" back onto a tracking course.

It will be understood that the difference in bridle cableforces is afunction of the off-tracking angle of the towed vessel and the forces acting on the towed hull which are measured by the forward extensions or displacements of the spring cylinder rods, these displacements being transmitted to two racks which control movement of a pinion. The resultant pin on translation is onehalf the algebraic difference of the two extensions and pinion movement is proportional in both magnitude and direction to the relative angle of the towed vessel with the tow cable.

On decrease of pull in bridle cable 86" and/or 86a", energy stored in the compression spring and the like starboard spring is available to straighten the course of the vessel from its turning movement by spring movement towards equilibrium and permits the springs in the rack return cylinders 220 and 222, which balance the effect on the racks of forward force path pull, to return the racks quickly to centered equilibrium. The rudder is thus quickly centered to reduce turning movement imparted by it to the towed vessel thereby removing a source of possible overshooting of the desired towed vessel track before the towed vessel reaches an ontrack" position. This efi'ect is also produced with the invention as illustrated in FIGS. 1 through 13.

It will be appreciated that either or both of the port or starboard force transmitting paths, as they are elastic and overlap across the stern of the towed vessel form an open circuit force path coupling together tow cable and towed vessel rudder and each force transmit ing pat can concurrently be extended forwardly an equal amount by pulling or by vessel forces or on relaxing of forces be contracted rearwardly together. This action in the modification of FIG. 14 only rotates the pinion so that no erroneous rudder movement occur and the towed vessel stays steady in its course. It will also be understood that mechanism of the force paths can move in opposite directions depending on the forces, onea greater amount than the other. For example, deflecting (side) forces could cause unequal bridle forces and therefore unequal rack motion. The system thus acts to generate a correcting rudder movement which is a function of the difference or error in bridle forces, one such difference in forces arising from off-tracking and other hulldeflecting forces arise from wave loading such as quartering or following seas. This construction provides for transfer of tow cable forces to the vessel and its rudder in a manner whereby system corrections made to correct off-track vessel movement are not necessarily wholly proportional to the amount the towed vessel is off course. Rather, the system of this invention uses towing forces to generate a correcting force and applies the correction before the towed vessel position becomes difficult or impossible to correct.

it can be noted that the amplitude of movement of the cylinder rods 96, and 96a and 96" and 96a" can be directly proportional to the pulling force on the bridle chains or cables since the compressing springs 100" are selected and an-anged to operate within their proportional elastic limit; and thus to maintain as closely as practicable their modulus of elasticity over their full operating range. Spring size, length and the number of its coils are selected so that under the normal operating conditions to be anticipated the compression spring movement provides the correct controlling movement.

It will be understood with reference to FlGS; l to 13, considering the port side as exemplz'y. 11:. the clamp M provides a coupling device that is a limiting means upcratiteiy cunneciing the buffering means cylinder rod or shaft 96 as a linking extension to its bridle cable and to th a force or response modif fying means and also links to cable 44" which provides a second 

1. An apparatus for automatically steering seagoing towed vessels comprising: towing means adapted to connect a towing vessel to the vessel to be towed; translation and rotation means positioned on said towed vessel adapted to be operatively connected to said towing means for providing translational and rotational movement, said translational movement produced from changes in force applied to said towing means by off-course tracking and said rotational movement produced from changes in force applied to said towing means by surging; and ruddersteering means positioned on said towed vessel and operatively connected to said translation and rotation means, said ruddersteering means movable to and from zero rudder turning positions only by said translational movement.
 2. The apparatus of claim 1 in which said towing means is a bridle means having aft extensions operatively connecteD to said translation and rotation means.
 3. The apparatus of claim 2 in which said rotation and translation means includes a set of dual independently slidable racks for translating and rotating a pinion therebetween; the aft end of one extension of the bridle means is attached to one rack and the aft end of the other extension of the bridle means is attached to the other rack, and the pinion is operatively connected to and rotatable in said rudder steering means, whereby changes in force produced by off-course tracking applied to said aft extensions cause said racks to slidably move to produce translational movement of said pinion, and changes in force produced by surging applied to said aft extensions cause said pinion to rotate with said translational and rotational motion cooperating to maintain said towed vessel on a tracking course with its towing vessel.
 4. The apparatus of claim 3 in which biasing means are operatively connected to said slidable racks to aid in returning said rudder-steering means to zero rudder turning position when the towed vessel has been returned to its tracking course.
 5. The apparatus of claim 2 in which said bridle aft extensions form therebetween an included angle of from about 5* to about 10*.
 6. The apparatus of claim 1 in which a buffering means is operatively connected between said towing means and said rotation and translation means for damping the forces produced in said towing means so that a smooth transmission of said force to said rotation and translation means is accomplished.
 7. The apparatus of claim 6 in which said buffering means is spring actuated.
 8. The apparatus of claim 1 in which said rudder-steering means includes a plurality of rudders which operate in unison and are operatively connected to said rotation and translation means for effecting steering of said towed vessel.
 9. An apparatus for automatically steering seagoing towed vessels comprising: towing means adapted to connect a towing vessel to the vessel to be towed; translation and rotation means positioned on said towed vessel adapted to be operatively connected to said towing means for providing translational and rotational movement, said translational movement produced from changes in force applied to said towing means by off-course tracking and said rotational movement produced from changes in force applied to said towing means by surging; rudder-steering means positioned on said towed vessel and operatively connected to said translation and rotation means, said rudder-steering means movable to and from a zero rudder turning position by said translational movement when said towed vessel is off the course of said towing vessel; and means operably connected to said translation and rotation means for providing fast translation movement from said zero rudder turning position for a portion of the movement of said rudder turning, slow translation of said rudder turning during further turning, and fast translation to return said rudder-steering means towards said zero rudder turning position.
 10. The apparatus of claim 9 in which a buffering means is operatively connected between said towing means and said rotation and translation means for damping the forces produced in said towing means so that a smooth transmission of said force to said rotation and translation means is accomplished.
 11. The apparatus of claim 9 in which said towing means have aft extensions operatively connected to said translation and rotation means.
 12. The apparatus of claim 9 in which the ratio of the fast rudder turning to the slow rudder turning is from about 2:1 to about 5:1.
 13. The apparatus of claim 9 in which the ratio of fast rudder turning to slow rudder turning is 2:1.
 14. The apparatus of claim 9 in which said rudder-steering means has means thereon for adjusting from one ratio to another to effect said fast and slow rudder turning positions.
 15. The apparatus of claim 9 in which said fast rudder turning Is through an arc of from about 2* to about 8* and said total rudder turning is through an arc of from about 10* to about 30* from zero to full rudder turning position.
 16. The apparatus of claim 9 in which said rudder-steering means employs a plurality of rudders that are responsive, in unison, to the movement of said translation means.
 17. The apparatus of claim 9 in which said translation and rotation means includes first and second independently slidable racks in geared relationship to a first pinion positioned on a pinion shaft, each one of said racks attached to one of the aft extension of said towing means; a second pinion positioned on said pinion shaft and positioned above said first and second racks, said second pinion free to rotate on said shaft and translatable when said first and second racks are moved; carriage means positioned over said first pinion having its travel parallel to the travel of said first and second slidable racks, said carriage means having an elongates slot therein with said second pinion positioned in its center when said rudder steering means is at zero turning position, and permitting said second pinion to translate in the slot to and from zero turning position; a third rack in fixed position with said carriage means operatively geared to said second pinion; a fourth rack slidable in said carriage means and operatively geared to said second pinion, means connecting said fourth rack with said rudder-steering means for effecting rudder positioning when said fourth rack is translated; carriage locking means for holding said carriage means in fixed position during said translation of said second gear in said slot by the movement of said first and second racks; and means for unlocking said carriage means when said second gear is at an end portion of said slot to allow said carriage means to be translated by translational movement of said second pinion, said translation of said carriage being geared to translate slower than said second pinion when turning on said third fixed rack, whereby said fourth rack is translated faster during translation of said second pinion in said slot than when the pinion is translating by movement of said carriage means to cause the rudder-steering means to turn fast during the first portion of its turning, slow during the final portion of its turning and then fast to return it towards zero rudder turning position after course correction has been made.
 18. The apparatus of claim 17 in which said carriage means has biasing means to effect smooth movement of said carriage means.
 19. The apparatus of claim 18 in which said carriage biasing means centers said carriage means after said pinion is returned toward zero rudder turning position after said rudder steering means has effected course correction.
 20. The apparatus of claim 17 in which said carriage means has means for centering said slot to position said second pinion at the center thereof after said rudder means is returned to zero rudder turning position.
 21. The apparatus of claim 17 in which said aft extensions form therebetween an included angle of from about 5* to about 10*.
 22. The apparatus of claim 17 in which said towing means are cables.
 23. The apparatus of claim 17 in which said first and second racks are biased to effect a smooth translation movement.
 24. The apparatus of claim 17 in which said first pinion produces rotation when equal forces are transferred to said first and second racks.
 25. The method of correcting the off-course tracking of seagoing towed vessels which comprises: transmitting changes in force produced in the towing means by off-course tracking to the stern of a towed vessel; amplifying said changes in forces and transferring them into translational and rotational motion; and moving a rudder steering means in response to said translational motion by first dividing the translational motion for effecting corrective steering into a fast portiOn and a slow portion, said fast portion first produced in an arc of rudder turning positions from zero rudder turning position, and said slow portion in the remainder of rudder turning positions until corrective steering is accomplished and then producing a fast rudder turning towards zero rudder turning position after the correction has been made.
 26. A system for steering a series of connected towed vessels which comprises connecting a plurality of vessels to be towed in tandem one to another and to a towing vessel by a towing means that provides a pair of tow extensions to the vessel being towed, each of the towed vessels in the series having rudder turning means operatively connected to a translation and rotation means, said translation and rotation means providing rudder turning from zero rudder turning position that is faster during a portion of its turning than the rudder turning during a latter portion thereof and then fast return rudder turning towards zero rudder turning position so that off-tracking of any one of the towed vessels actuates its translation and rotation means to effect rudder changes to bring the towed vessel that is off course back on course. 